Cambridge Forecast Group Blog

GLOBALIZATION AND SECRECY

Globalization and Secrecy:

Signals Intelligence and the Rise of the Surveillance State

Before there was the NSA and before

“Enigma” and Bletchley Park in WW II, there

was the British Room 40:

Zimmermann Telegram

The Zimmermann Telegram (or Zimmermann Note; German: Zimmermann-Depesche; Spanish: Telegrama Zimmermann) was a coded telegram dispatched by the Foreign Secretary of the German Empire, Arthur Zimmermann, on January 16, 1917, to the German ambassador in Washington, Johann von Bernstorff, at the height of World War I. On January 19, Bernstorff, per Zimmermann’s request, forwarded the Telegram to the German ambassador in Mexico, Heinrich von Eckardt. Zimmermann sent the Telegram in anticipation of the resumption of unrestricted submarine warfare by the German Empire on February 1, an act which German chancellor Bethmann-Hollweg feared would draw the neutral United States into war on the side of the Allies[1]. The Telegram instructed Ambassador Eckardt that if the United States appeared likely to enter the war he was to approach the Mexican government with a proposal for military alliance. He was to offer Mexico material aid in the reclamation of territory lost during the Mexican-American War, specifically the American states of Texas, New Mexico, and Arizona. Eckardt was also instructed to urge Mexico to help broker an alliance between Germany and Japan.

The Zimmermann Telegram was intercepted and decoded by the British cryptographers of Room 40.[2] The revelation of its contents in the American press on March 1 caused public outrage that contributed to the United States‘ declaration of war against Germany and its allies on April 6.

Room 40

In the history of cryptography, Room 40 (latterly NID25) was the section in the Admiralty most identified with the British cryptography effort during World War I.

It was formed shortly after the start of the war in October 1914. Admiral Oliver, the Director of Naval Intelligence, gave intercepts from the German radio station at Nauen near Berlin to Director of Naval Education Alfred Ewing, who constructed ciphers as a hobby. Ewing recruited civilians such as William Montgomery, a translator of theological works from German, and Nigel de Grey, a publisher.

A German naval codebook, the Signalbuch der Kaiserlichen Marine (SKM), and maps (containing coded squares) had been passed on to the Admiralty by the Russians, who had seized them from the German cruiser Magdeburg when it had run aground off the Estonian coast on 26 August 1914. Two copies of the four that the warship had been carrying were recovered; one was retained by the Russians and the other passed to the British. In October, 1914 the British also obtained the Imperial German Navy‘s Handelsschiffsverkehrsbuch (HVB), a codebook used by German naval warships, merchantmen, naval zeppelins and U-Boats. This had been captured from the German steamer Hobart by the Royal Australian Navy on 11 October. On 30 November a British trawler recovered a safe from the sunken German destroyer S-119, in which was found the Verkehrsbuch (VB), the code used by the Germans to communicate with naval attachés, embassies and warships overseas.[1]

The section retained “Room 40” as its informal name even though it expanded during the war and moved into other offices. It was wound up in February 1919. It has been estimated that Room 40 decrypted around 15,000 German communications[2], the section being provided with copies of all interceptable communications traffic, including wireless and telegraph traffic. Until May 1917 it was directed by Alfred Ewing, and then direct control passed to Captain (later Admiral) Reginald ‘Blinker’ Hall, assisted by William Milbourne James[3].

Room 40 played an important role in several naval engagements during the war, notably in detecting major German sorties into the North Sea that led to the battles of Dogger Bank and Jutland as the British fleet was sent out to intercept them. However its most important contribution was probably in decrypting the Zimmermann Telegram, a cable from the German Foreign Office sent via Washington to its ambassador Heinrich von Eckardt in Mexico.

In the cable’s plaintext, Nigel de Grey and William Montgomery discovered German Foreign Minister Arthur Zimmermann making an offer to Mexico of United States territory (Arizona, New Mexico, & Texas) as an enticement to join the war as a German ally. The cable was passed to the U.S. by Captain Hall, and a scheme was devised (involving a still unknown agent in Mexico and a burglary) to conceal how its plaintext had become available and also how the U.S. had gained possession of a copy. The cable was made public by the U.S., who shortly thereafter entered the war on the Allied side.

Other staff of Room 40 were Frank Adcock, Francis Birch, William Nobby Clarke, Alastair Denniston and Dilly Knox.

In 1919, Room 40 was run down and merged with the British Army‘s intelligence unit MI1b to form the Government Code and Cypher School (GCCS), later housed at Bletchley Park during World War II and subsequently renamed Government Communications Headquarters (GCHQ) and relocated to Cheltenham.

Notes

1. Massie. Castles of Steel. pp. 314–317.
2. Lieutenant Commander James T. Westwood, USN. “[http://www.nsa.gov/public_info/_files/cryptologic_spectrum/electronic_warfare.pdf Electronic Warfare and Signals Intelligence at the Outset of World War I]”. NSA. http://www.nsa.gov/public_info/_files/cryptologic_spectrum/electronic_warfare.pdf. Retrieved 2009-05-04.
3. Johnson. British Sigint. pp. 32.

References

• Andrew, Christopher (1986). Her Majesty’s Secret Service: The Making of the British Intelligence Community. New York: Viking. ISBN 0-670-80941-1.
• Beesly, Patrick (1982). Room 40: British Naval Intelligence, 1914–1918. New York: Harcourt, Brace Jovanovich. ISBN 0-15-178634-8.
• Johnson, John (1997). The Evolution of British Sigint, 1653–1939. London: H.M.S.O..
• Tuchman, Barbara W. (1958). The Zimmerman Telegram. New York: Ballantine Books. ISBN 0-345-32425-0.
• Koerver, Hans J. (2008). Room 40: The fleet in action. Steinbach: LIS Reinisch. ISBN 978-3-902433-76-3.
• Koerver, Hans J. (2009). Room 40: The fleet in being. Steinbach: LIS Reinisch. ISBN 978-3-902433-77-0.